Oxygenated diode page.

Large area and miniature segmented detectors

 N-side read-out of segmented detectors

In the development of silicon microstrip detectors for high energy physics applications the Liverpool laboratory clearly established the advantage of reading out finely segmented devices from the n-type implants. Silicon detectors made with n-type bulk silicon undergo space charge sign inversion after being irradiated with hadron to a dose of a few 10¹³ cm^-2  The standard diode structure for segmented detectors used in high energy physics is p-strips implanted into a lightly doped n-type substrate. With this geometry, after type-inversion, the high electric field is on the opposite side to the read-out strips, resulting in a reduced charge collection vs bias (CCE(V)) at low voltages. The CCE(V) can be improved by segmenting and reading out the n-side of the detector (n-in-n geometry). Very good performance after irradiation has been achieved with this geometry. An example of the advantages of this geometry is shown here. The n-side read-out concept is now widely accepted. The most exposed silicon detectors of the LHC experiments (ATLAS and CMS pixels and LHCb-VELO microstrips) all use n-side read-out.

 P-type silicon detectors

The limitation with the n-in-n devices is the higher processing cost, and, to a lesser extent, that the junction side (and the high electric field) is on the opposite side before irradiation. Both the migration of the junction after type inversion and the extra cost due to the double-sided processing can be avoided by using a p-type bulk substrate. Concerning the CCE(V) properties as a function of the cumulated fluence, an improvement similar to the n-in-n read-out was expected with p-type substrates. To investigate this issue we first produced ATLAS SCT geometry, p-type substrate detectos with p-stop interstrip isolation. The production was successful and proved the feasibility and the improvements of this solution. The irradiation fluence was up to LHC tracker levels (~ 4. 10¹⁴ p cm^-2). To further study the radiation hardness of these detectors to super-LHC levels we produced miniature n-in-p capacitively coupled, polysilicon biassed microstrip detectors (1x1 cm^-2, 100 strips). These miniature devices allowed us to investigate the charge collection properties up to 7.5 10¹⁵ p cm^-2. I report here the extremely positive results we have obtained.

P-type detectors page.

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RECENT PUBLICATIONS AND TALKS   Some of this material has been put together for conference presentations and/or articles. Here I list some recent presentations.   VERTEX 2008 …or the 17th International Workshop on Vertex Detectors, Utö Island, Sweden, July 28–August 1, 2008. You find here the talk. Barcelona 2008 .....or the 3rd Workshop on Advanced Silicon Radiation Detectors (3D and P-type Technologies), Barcelona 14-16 April 2008. INSTR08 ..... or the 10th International Conference on Instrumentation for Colliding Beam Physics, Budker Institute of Nuclear Physics, Siberian Branch of Russian Academy of Science, Novosibirsk, Russia, February 28 - March 5, 2008. VLC2007 .....or the ATLAS Tracker Upgrade Workshop, Valencia (SP), 12-14 December 2007. IEEE 2007 ..... or the Nuclear Science Symposium and Medical Imaging Conference, October 27 – November 3, 2007, Honolulu (Hawaii), USA. ou can find here my article. VERTEX 2007 ...... or the 16th International Workshop on Vertex detectors, September 23-28, 2007, Lake Placid, NY, USA. You can find here my talk 9th IWORID ....or the 9th International Workshop on Radiation Imaging Detectors, Erlangen, Germany 22-26 July 2007. You can find here my talk.  VCI 2007  …or the 11th Vienna Conference on Instrumentation, Vienna, Austria, February 19-24 2007. AHLUTW '06 …or the ATLAS High Luminosity  Upgrade Tracker Workshop, Liverpool: 6 - 8 December 2006.You find here my talk.  STD6 ... or 6th International “Hiroshima” Symposium on the Development and Application of Semiconductor Tracking Detectors, see http://scipp.ucsc.edu/STD6/. You can find here my talk.  TIME'05 …or the Workshop on Tracking In high Multiplicity Environments, October 3-7, 2005, Zurich, Switzerland. You find here the talk.  Genova '05 ... the ATLAS tracker upgrade workshop, in Genova (Italy) 18-20 July 2005, see http://agenda.cern.ch/fullAgenda.php?ida=a053875. You can find here my talk.  Kreuth '05 …or the 10th European Symposium on Semiconductor Detectors, June 12 - 16, 2005, Kreuth , Germany. You find here the talk. RESMDD'04 …or the 5th International Conference on Radiation Effects on Semiconductor Materials Detectors and Devices October 10-13, 2004, L.go E. Fermi 2, Florence, Italy.  You find here the talk. VCI 2004 …or the 10th Vienna Conference on Instrumentation, Vienna, Austria, February 16-21 2004. You find here the article. ERICE 2003 …or the workshop on Innovative Detectors for Supercolliders, Erice (TP), Italy, 29th Sep.-03 Oct. 2003.  You find here the talk and the article. ELBA 2003 …or the 9th Pisa Meeting on Advanced Detectors, La Biodola, Isola d'Elba, 25-31 May 2003  November 3-8, 2002. You find here the poster and the article. VERTEX 2002 …or the 11th International Workshop on Vertex Detectors, Ohana Keauhou Beach Resort, 78-6740 Alii Drive Kailua-Kona, Hawaii  November 3-8, 2002. You find here the talk and the article. ELMAU 2002 … or the  9th European Symposium on Semiconductor Detectors, New Developments on Radiation Detectors, Schloss Elmau, June 23 - 27, 2002. You find here the article. ISM2E-YS ... invited talk at the International Symposium of Young Scholars on Mechanical and Material Engineering for Science and Experiments, 11-16th of August 2001 Changsha, Hunan Province, China. Here you can find the transparencies of my talk. 4th STD ... or the 4th International Symposium on Development and Application of Semiconductor Tracking Detectors (Hiroshima, March 22-25 2000). Here you can find the transparencies of my talk. RD 99 ... or the 4th International Conference on Large Scale Applications and Radiation Hardness of Semiconductor Detectors (Firenze, Italy, 23-25 June 1999). Here you can find the article. Radecs 99 ....or the 5th EUROPEAN CONFERENCE: Radiation and its effects on components and systems (Abbaye de Fontevraud, FRANCE, Maine et Loire, 13 - 17 septembre 1999). Here you can find the poster  and the article. SEMINARS University of Glasgow 06/12/2007, Here is the talk. University of Bonn 15/12/2005, Here is the talk. IFIC-Valencia 21/05/2004, Here is the talk.   If you want to take a look to my thesis (again on silicon detectors) PhD thesis (Université Joseph Fourier - Grenoble I, France): The effect of hadron irradiation on the electrical properties of particle detectors made from various silicon materials. N.B. Text is in English. My Publication List. For comments etc. please contact Gianluigi Casse Contact Information E-Mail:  <gcasse@hep.ph.liv.ac.uk> Phone:  +44 151 794 3399 Fax:  +44 151 794 3441 Postal Address: University of Liverpool - Department of Physics Oliver Lodge Laboratory Oxford Street Liverpool L69 7ZE United Kingdom Last modified: 07/08/2008